Last updated on
Why Me? A Look at the Risk Factors Behind a Blood Clot
Being diagnosed with a blood clot, whether it appears as deep vein thrombosis (DVT) or pulmonary embolism (PE), is a life changing experience. Patients with DVT or PE must deal with many changes. They may need to adjust what they eat, what medications they’re taking, what hobbies they enjoy, and more. It can cause a great amount of anxiety and uncertainty.
If you’ve been diagnosed with PE or DVT, you might be left with many unanswered questions, feeling very confused about why this happened to you. In many patients, the ultimate cause of thrombosis is still largely unknown. However, there are factors that can make you more likely to develop a blood clot.
Provoked vs. Unprovoked
You may have heard the terms “provoked” and “unprovoked” when discussing your blood clot with your doctors. These terms are related to why your blood clot happened. Determining if your blood clot was provoked or unprovoked can help your doctors decide what treatment is right for you. If it was a provoked blood clot, you had a major clinical risk factor for thrombosis. These risk factors can include surgery, trauma, pregnancy, hormonal therapy, and immobility.
If your blood clot was unprovoked, you have no major clinical risk factors, but could instead have underlying risks. These could include a family history of thrombosis, active cancer, and thrombophilia.
Learn more about provoked vs unprovoked blood clots in our article “Provoked vs. Unprovoked Clots: What’s the Difference?”
In order to understand what puts you at risk for a blood clot, it’s important to understand why blood clots occur.
“In deep vein thrombosis (DVT), blood clots develop in the leg or pelvis veins in the absence of obvious damage to the vessel. Within the vessel, a combination of microscopic injury to the vein wall along with abnormal blood flow and a propensity for blood clots all contribute to DVT formation,” explained Dr. Aaron Aday, an Instructor in Medicine in the Division of Cardiovascular Medicine Vanderbilt University Medical Center, in The Clot Connection: Thrombosis, Heart Attack, and Stroke.
“Inflammation and underlying genetic factors likely predispose people to DVT, and other risk factors such as cancer or immobility also increase risk for DVT. If a portion of the DVT dislodges, it can travel through the veins and relocate in the pulmonary arteries, thereby becoming a pulmonary embolism (PE).
Here are different risk factors that can predispose patients to blood clots:
- Genetics – Genetics can make some patients more prone to blood clots. This happens when a genetic mutation has occurred and is then passed down a family line. Two of these mutations include Factor V Leiden and prothrombin gene mutation. Factor V Leiden causes thrombophilia, and the prothrombin mutation causes the body to over produce thrombin.
- Cancer – Thrombosis is the second most common cause of death in cancer patients. Cancer itself is a risk factor, but so are the chemotherapy medications and the surgeries involved in cancer treatment.
- Inflammation – Different diseases, such as metabolic syndrome, diabetes, and rheumatoid arthritis, cause inflammation in the body, which can lead to thrombosis. The connection between thrombosis and inflammation is complex and currently being researched.
- Hormone Therapies – Oral contraceptives, menopausal treatments, and other forms of hormone therapy can put a patient at risk for thrombosis. The estrogen in the medications can cause increased activated protein C resistance, increased thrombin activation, and more. That said, only 1 in 1,000 women per year who are on the birth control pill will develop a clot. Always share any concerns you have about medications with your doctor.
- Surgery – Your risk for developing a blood clot is higher after you’ve had surgery. Hip and knee replacement surgery patients are especially susceptible, because those surgeries impact the bone marrow cavity. Bone marrow fat can enter the body and cause blood clots to form. Because of this, you should discuss your risk of developing thrombosis with your surgeon before any procedure. Some patients are placed on blood thinners during their surgery, while others wear pneumatic compression boots post-operation.
- Pregnancy – Thrombosis affects pregnant women up to 10 times more than non-pregnant women of the same age. Specialized treatments for pregnant women at risk of developing thrombosis are available. If you have a history of blood clots and are pregnant (or plan on becoming pregnant) it’s important to talk with doctor about your treatment plan.
- Immobilization – Patients who are sedentary, or unable to move often, are at risk for thrombosis. This includes people who live sedentary lives, who sit for prolonged periods of time or aren’t very active. Even very active people can be at risk if they sit for a prolonged period, such as for a long plane ride. It also includes people who may be unable to move, such as patients in the hospital on prolonged bed rest.
- Lifestyle – Certain unhealthy lifestyles can predispose people to blood clots. Smoking is one unhealthy lifestyle choice that increases risk, as is obesity. Eating healthy, exercising regularly, and making health-conscious choices can help decrease your risk of thrombosis.
People develop blood clots for many different reasons. While the eight risk factors listed above can provide some guidance, there are many other risk factors that people face. Some of these risks are known, while others are yet to be discovered. By determining what your risk factors are, you can uncover why you may have developed a blood clot and how to prevent one in the future.
Always talk to your doctor about any concerns you may have. Only they can help guide you through your personal risk factors and future care.